Educational apparatus



Patented Feb. l929.

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Application filed Ianuarys'l, 192d, Serial No. 84,0l5,'and.in Germany February 1925;

My invention relates to means for assisting the blind in mathematical exercises and it has particular relation to devices which are formed from wire and provided with means 5 permitting the insertion of such devices into supports.

At the present time the only means by which the blind may perform mathematical exercises are strings stretched between pins.- W Such method of instruction has been markedly insuficient, in fact so much so that it has been necessary to exempt the blind from-examinations in mathematics, whereby many fields of science were barred to such persons.

ematical values, products, signs, and the like,

bodily with wire, the wire being provided terserves as a working plane, whereon the niethernatical devices may he arranged as 29 rality of exercises.

Several elements are illustrated by way of example in the accompanying drawing, in which: v c

Figure 1 illustrates an element oi my invention representing a dash line;"

Fi 2 illustrates an element representing a re "ical sign;

8 illustrates a round bracket; and Fig. t illustrates the manner which certain devices, including another device constructed in accordance with my invention and "representing a semi-circle, are used insolva problem.

' Referring generally to the drawing, it-will he seen that representations of various indicia are formed oi wire, the end portions of the latter being bent 0 from the intermediate porp tion ineach case and being taperedto relatively sharp points. In this manner circles, semi circles-,ellipses, ellipsoid arcs, straight and curved lines of any desired size may be repre sented and constructed so that they can be :plaoed together in any desired formation.

radical signs, square and round Moreover,

designation of brackets, figures or characters,

drawings, a wire 5 is provided with undula- My invention consists in representing inatln" required, and then removed, to performs plu- .my invention in the sons may practice mathematical exercises,

formed in. accordance with my in- 'vention. showing be considered as illustrativeonly,

scope of the appended claims 'jplane.

angles and the like may also be formed and provided with sharp points.

Referring particularly to Fig. 1 of the tions, these undulations being positioned in a plane extending vertically and between the,

downwardly bent pointed ends, (l -6, i. e., in.

the plane of the sheet on which the drawing is illustrated. The crests of the wire are indicated at 7--7, while the valleys or depressions are indicated at 8--8. When such adevice is felt by a blind person the crests or apices Tare distinguished as being raised, whereas the depressions 8 are sensed as. interruptions, with the result that the device as a whole represents to a blind person a broken or dash line.

Figure 2 "represents a radical sign 13 pro-. vided with pointed ends 1 to permit its placement on a flexible or impres'sihle surface and Figure 3 illustrates a round bracket 15 having pointed ends 16. I

ln Fig. 4: l have shown the manner in which it'll blind persons may utilize devices embodying Here a vertical line ll is erected on the diameter E9 of a semi-circle represented by a wire 10 having an arcuate intermediate portion lying in aplan'e substantially atright angles to the poi ted ends of the wire, and all the It is .to understood that the above signs,

and other devices, are only illustrativeund that many. other such values and products, in fact all the needed indicia whereby blind per,

ma be y I therefore wish'that the present and that the invention'he limited only by the. and the prior. art.

'lclaim;

1. Devices for assisting blind persons in mathematical exercises comprising the reppesentation of a dashi-line consisting of a wire having undulations therein extending in a solution of a problem,

vertical plane and. said wire being provided f" with end portion's'bent at angles to permit the H positioning or said devices on a. .,work1 ng 2. A device for assisting blind persons in mathematical exercises, comprising a wire formed with two end portions and a curved intermediate: portion, said end portions being 5 bent ofi from said intermediate portion and extending substantially parallel to each other whereby they may be inserted in a supporting member to maintain said intermediate portion in fixed relation to said supportin member to convey to blind persons throng their sense of touch impressions of mathematical figures or like indicia.

In testimony whereof I afiix my signature.

MARIE ANTONIE MAHLER. 

